A routine for color marking using oxide layers and laser-induced periodic surface structures is presented. Titanium and alloys thereof are marked with pixelated graphics at a high resolution with tempering colors. A computational approach for the laser path calculation enables a fast-forward marking of complex designs. The color map attained from a laser parameter studies enables vivid coloration. The minimal color pixel size is given by the optical setup and laser wavelength at near-infrared and green radiation to the focal spot size. A pixel size of 35 and 20 μ m was reached within this study, and no cross talk and distinctness between adjacent colors were observed. The oxide layer growth is sensitive on the applied laser strategy and parameter setting; however, a set of stable coloration conditions is conceived. Hitherto, fine color nuances in blue unravel the unique potential of this approach by oxidizing the substrate leading to a defined oxide layer thickness at a high repetition rate below the threshold fluence. Additionally, ultrashort pulsed laser pulses below 10 ps enable the generation of laser-induced periodic surface structures. In the low spatial frequency regime, these structures are correlated with the polarization direction of the laser light. Afterward, diffraction gratings with rotated spatial periodicity are manufactured using a half-wave plate. This allows forgery-proof marking strategies, where both mechanisms could be superimposed to increase the information density and complicating counterfeit product labeling.

中文翻译：

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超短脉冲激光打标和着色 Ti-6Al-4V

介绍了使用氧化层和激光诱导的周期性表面结构进行彩色标记的程序。钛及其合金标有高分辨率的像素化图形和回火颜色。用于激光路径计算的计算方法可以快速标记复杂设计。从激光参数研究中获得的颜色图可以实现生动的着色。最小彩色像素尺寸由光学设置以及近红外和绿色辐射下的激光波长给定焦斑尺寸。在这项研究中达到了 35 和 20 μm 的像素尺寸，并且没有观察到相邻颜色之间的串扰和清晰度。氧化层生长对应用的激光策略和参数设置很敏感；然而，设想了一组稳定的着色条件。迄今为止，蓝色的细微颜色差异揭示了这种方法的独特潜力，它通过在低于阈值能量密度的高重复率下氧化基板导致确定的氧化层厚度。此外，低于 10 ps 的超短脉冲激光脉冲能够生成激光诱导的周期性表面结构。在低空间频率范围内，这些结构与激光的偏振方向相关。然后，使用半波片制造具有旋转空间周期性的衍射光栅。这允许防伪标记策略，其中两种机制可以叠加以增加信息密度并使假冒产品标签复杂化。